NAT Gateway Tunnel Mobility for Seamless IP Handover
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Solution Overview
Problem
Existing communication protocols for network address translation in tunnel mobility, such as Mobile IP and MOBIKE, face challenges in maintaining continuous communication sessions as access terminals move between different access routers without imposing processing overhead on the terminals, especially when secure tunnels are involved.
Innovation Solution
Establishing network tunnels between an access gateway and multiple access routers, with the access gateway performing source and destination address translation to maintain a consistent public address for access terminals, allowing them to maintain communication sessions across router switches without the need for additional tunnels or processing overhead on the terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Mobile IP or MOBIKE protocols are used to maintain network connectivity during terminal movement, then continuous communication sessions are achieved, but processing overhead is imposed on the access terminals
Solution Approach 1:
The patent introduces a network address translation (NAT) device as an intermediary between the access terminal and the correspondent node. This NAT device maintains the binding between the terminal's home address and care-of address, performing address translation operations centrally rather than requiring the terminal to execute complex Mobile IP or MOBIKE protocol processing. The terminal simply communicates through the NAT device without needing to understand or process mobility management protocols, thus maintaining continuous communication while eliminating processing overhead on the terminal.
2Adaptability or versatility
If secure tunnels are established for each access router to maintain mobility, then seamless router switching is achieved, but device complexity increases
Solution Approach 1:
The patent extracts the tunnel management and security association functions from the access terminal and concentrates them in the NAT device. Instead of requiring the terminal to establish and manage multiple secure tunnels when switching between access routers, the NAT device maintains a single persistent tunnel or connection with the correspondent node. The terminal's mobility is handled transparently by the NAT device, which updates its own routing information without involving the terminal in tunnel establishment or reconfiguration, thus achieving seamless router switching while reducing device complexity.
3Reliability
If multiple network tunnels are established for terminal mobility management, then continuous connectivity is maintained, but loss of time occurs due to tunnel setup and updates
Solution Approach 1:
The patent implements preliminary action by having the NAT device pre-establish and maintain the binding between the terminal's home address and care-of address before actual data transmission begins. When the terminal moves to a new access router, the NAT device has already prepared the address translation mappings, allowing seamless forwarding of packets without requiring time-consuming tunnel re-establishment or protocol negotiation. The correspondent node's routing information is pre-configured through the NAT device, eliminating delays associated with dynamic tunnel setup during mobility events.
Data Source
AI summary
An access terminal identity based mobility is provided in which a first network tunnel is established between an access gateway and a first access router, and a second network tunnel is established between the access gateway and a second access router. At the access gateway, source addresses of packets sent from an access terminal to a remote correspondent node are translated by replacing the local address of the access terminal with the public address of the access terminal. The access terminal continuously maintain a communication session with the correspondent node as the access terminal moves from a first location to a second location and switches from accessing the first access router to accessing the second access router. A mapping between the local address and the public address is updated as the access terminal switches from the first access router to the second access router.